Eschtruth A.K.

Quantitative Assessment of Habitat Preferences for the Puerto Rican Terrestrial Frog, Eleutherodactylus coqui

Beard, Karen H.; Mccullough, Sarah; Eschtruth, Anne K. 2003. Quantitative Assessment of Habitat Preferences for the Puerto Rican Terrestrial Frog, Eleutherodactylus coqui. Journal of Herpetology, Vol. 37, No. 1, :10-17,.

Abstract: 
We conducted a quantitative analysis of adult and juvenile Eleutherodactylus coqui (coquí) habitat preferences in Puerto Rico. The analysis consisted of two surveys: one to quantify potential habitat and another to quantify habitat use. Coquís were found to use most habitats available to them; however, adults and juveniles preferred different plant species, habitat structural components, and heights from the forest floor. Adult and juvenile coquís had opposite associations with many important plant species in the forest (e.g., Prestoea montana and Heliconia carabea) and habitat structural components. Adults had a negative association with leaves and a positive association with leaf litter. Juveniles showed the opposite trend. Adults were more evenly distributed with respect to height than were juveniles, with adults preferring heights around 1.1 m and juveniles preferring heights closer to the forest floor. The quantitative survey technique for determining habitat preferences used in this study generally confirmed coquí habitat preferences known from qualitative assessments.

Quantitative Assessment of Habitat Preferences for the Puerto Rican Terrestrial Frog, Eleutherodactylus coqui

Quantitative Assessment of Habitat Preferences for the Puerto Rican Terrestrial Frog, Eleutherodactylus coqui
Karen H. Beard, Sarah McCullough and Anne K. Eschtruth
Journal of Herpetology
Vol. 37, No. 1 (Mar., 2003), pp. 10-17

Abstract: 
We conducted a quantitative analysis of adult and juvenile Eleutherodactylus coqui (coquí) habitat preferences in Puerto Rico. The analysis consisted of two surveys: one to quantify potential habitat and another to quantify habitat use. Coquís were found to use most habitats available to them; however, adults and juveniles preferred different plant species, habitat structural components, and heights from the forest floor. Adult and juvenile conquís had opposite associations with many important plant species in the forest (e.g., Prestoea montana and Heliconia carabea) and habitat structural components. Adults had a negative association with leaves and a positive association with leaf litter. Juveniles showed the opposite trend. Adults were more evenly distributed with respect to height than were juveniles, with adults preferring heights around 1.1 m and juveniles preferring heights closer to the forest floor. The quantitative survey technique for determining habitat preferences used in this study generally confirmed coquí habitat preferences known from qualitative assessments.

The effects of the frog Eleutherodactylus coqui on invertebrates and ecosystem processes at two scales in the Luquillo Experimental Forest, Puerto Rico

The Effects of the Frog Eleutherodactylus coqui on Invertebrates and Ecosystem Processes at Two Scales in the Luquillo Experimental Forest, Puerto Rico
Karen H. Beard, Anne K. Eschtruth, Kristiina A. Vogt, Daniel J. Vogt and Frederick N. Scatena
Journal of Tropical Ecology
Vol. 19, No. 6 (Nov., 2003), pp. 607-617

Abstract: 
Determining the ubiquity of top-down control effects of predators on their prey and ecosystem processes is important for understanding community and ecosystem-level consequences that may result from predator loss. We conducted experiments at two spatial scales to investigate the effects of terrestrial frogs (Eleutherodactylus coqui) on aerial and litter invertebrates, plant growth and herbivory, and litter decomposition. At both scales, frogs reduced aerial invertebrates and leaf herbivory, but had no effect on litter invertebrates. At the smaller scale, frogs increased foliage production rates, measured as the number of new leaves and new leaf area produced, by 80% and decomposition rates by 20%. The influence of E. coqui on increasing primary productivity and decomposition rates at the smaller scale appeared to be a result of elimination and excretion rather than of controlling prey. While the results provide evidence for frogs controlling herbivorous prey at both scales, species effects on ecosystem processes were only detectable at the smaller scale. The results highlight the difficulties in conducting experiments at large spatial scales. The findings from this study imply that the loss of amphibians and other species of higher trophic levels may affect nutrient cycling rates in tropical forests.
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